ByNicole Winfield, Associated PressMarch 5, 2013

VATICAN CITY — The Sistine Chapel closed to visitors on Tuesday and construction work got under way to prepare it for the conclave that will choose the next pope, but five cardinals had yet to arrive for the preparatory meetings designed to acquaint themselves with one another and discuss the state of the Catholic Church.

The Vatican insisted nothing was amiss and that the five cardinals would be present in the coming days. But their absence prompted questions about what could possibly be more important than participating in these days of discernment and discussion to decide who will succeed Benedict XVI, who retired last week.

Cardinals in Rome stressed the importance of these sessions to discuss the problems of the church and to get to know one another because there is no clear front-runner in the election. They seemed to be in no hurry to even officially set a date for the conclave.

That said, Di Nardo said he hoped to be home for Holy Week, which starts March 24 with Palm Sunday. When challenged about the tight timeframe, Di Nardo acknowledged the importance of the task at hand and said his archdiocese in Galveston-Houston Texas could do without him if need be.

Meanwhile, preparations for the conclave continued with Michelangelo's frescoed Sistine Chapel closing at 1 p.m. to visitors, one of the first visible signs that the election was nearing. Construction work involves installing a false floor to cover anti-bugging devices and even it out, as well as installing the stove where the ballots will be burned.

A total of 110 of the 115 voting-age cardinals attended the second day of preparatory meetings Tuesday to organize the conclave, the Vatican said.

Those still making their way to Rome were: Egyptian Patriarch Antonios Naguib, and Cardinals Karl Lehmann of Germany, Jean-Baptiste Pham of Vietnam, Kazimierz Nycz of Poland and John Tong Hon of Hong Kong, the Vatican said.

"Everyone knows how to evaluate his commitments," the Vatican spokesman the Rev. Federico Lombardi said when asked why the cardinals were still absent. "They know they have the obligation and commitment to come for the conclave, and they know the congregations have begun and are making their plans to arrive."

He noted that one cardinal had an important meeting of bishops to attend to; another reported having a speaking engagement.

During the second day of pre-conclave meetings, cardinals asked for information about the management of the Vatican bureaucracy — and managers responded — after some cardinals said they wanted to get to the bottom of allegations of corruption and cronyism in the Holy See's governance.

Citing his pledge of secrecy, Lombardi refused to say who responded and whether the questions referred to the leaks of Vatican documents, which exposed evidence of turf battles and political intrigue.

Also Tuesday, cardinals signed off on a telegram sent to Benedict XVI thanking him for his "brilliant" ministry and his "untiring work in the vineyard of the Lord."

And the Vatican showed off the urns into which the cardinals will place their ballots, the same silver and bronze flying-saucer-like urns used in the 2005 conclave that elected Cardinal Joseph Ratzinger pope.